Thin film-coated polymer webs are utilized in many applications requiring conductive, semiconductive, insulating, or reflective coatings and are particularly useful for making thin film electronic devices such as thin film photovoltaic devices. A major concern with thin film-coated polymer webs is the purity of the polymer web. It is important that the polymer web b.RTM.substantially free of contaminants. If not removed from the polymer web, the contaminants can impair the performance of the thin film electronic devices which are formed on the polymer web. Thin film photovoltaic devices, in particular, are especially susceptible to the presence of contaminants in the polymer web.
Perhaps the most popular method of purifying the polymer web is the thermal outgassing method. In this method, the polymer web is heated in a vacuum at a temperature approaching the thermal limits of the polymer web.
U.S. Pat. No. 3,436,468 teaches that the exposure of portions of an inorganic polymer to electron beam radiation decreases the electrical resistance of the exposed portion. This change in resistance allows electroless plating of metal to those areas exposed.
Equsa, in a paper published by the Journal of Material Science, vol. 23, no. 8, pp. 2753-2760 (August (1988), describes changes in the properties of a polymer matrix, such as Young's modulus and ultimate strength, as a function of radiation exposure.
Krishnaswamy et al., SPIE-International Society of Optical Engineering, vol. 773, pp. 159-164 (1987), describes the direct patterning of polyimide coated on a silicon wafer using a grid line on an electron microscope as a mask. The polyimide is cross-linked as a consequence of exposure to electron beam radiation, thus providing an etch mask for patterning onto the polyimide.
Ferl et al., Proceedings of the IEEE Transactrons (of) Nuclear Science, vol. NS-28, no. 6, pp. 4119-4124 (December 1981) describes the effects of simulated space radiation on polyimide.